Element for insulating the surface of a molten product



Aug. 13, 1957 .15 R. v. MARTINY 2,802,656

ELEMENT FOR INSULATING THE SURFACE OF A MOLTEN PRODUCT Filed May 20, 1953 FIG.2.

7 ill/I111 FIG.5'.

, INVENTOR. JEAN RAYMOND VALERE MART/NY ATTORNEY.

Unit States at O.

ELEMENT FOR INSULATING THE SURFACE OF A MOLTEN PRODUCT Jean Raymond Valre Martiny, Rouen, France Application May 20, 1953, Serial No. 356,272

Claims priority, application France May 21, 1952 6 Claims. (Cl. 263-1) In metal or metal alloy smelting furnaces, of the directflame or radiation type, it is essential, in order to avoid oxidizing, to insulate the surface of the molten product from the furnace atmosphere. Such an insulation is conventionally achieved by means of products called fluxes.

Such a method has certain drawbacks among which should be mentioned the poor thermal conductivity of the fluxes which, placed between the flame or the furnace radiating source and the product to be melted, thus cause an appreciable waste in the calorific energy supplied to the furnace.

The object of my invention is to provide a new process for insulating the surface of molten products in furnaces, more particularly in the direct-flame or radiating type furnaces.

My invention consists mainly in ensuring the protection of the molten-product surface through fireproof bodies floating on the said surface and which are good heat-conducting substances.

My invention also embodies some other arrangements as indicated hereafter and preferably used jointly with the principal arrangement as mentioned above.

My invention particularly covers some methods for applying and effecting such arrangements as also the fireproof bodies referred to above, the components and tools appropriate for making them and also the assemblies incorporating such bodies.

By way of example, and for providing a better understanding of my invention, I will now disclose the manner of executing the same in a particular embodiment thereof as illustrated in a non-limiting sense in accompanying drawing.

In said drawing:

Figure 1 is a vertical view of a fire-proof body made in accordance with my invention;

Figure 2 is a plane view of the same fire-proof body;

Figure 3 is a diagrammatic lengthwise section of a furnace using the protection process according to my invention;

Figure 4 is a diagrammatic plane view of part of the bath surface in the same furnace; and

Figure 5 is a vertical section of a modification of a fire-proof body variant made according to my invention.

When it is desired to ensure the protection of a furnace bath according to my invention, the procedure is as follows:

Thin bodies 1 (see Figure l) are made of fire-proof and good heat-conducting substances, for instance, of silicon carbides or of fire-proof compounds based on preferably oriented graphite, and these thin bodies 1 are given the shape of a hexagonal plate (see Figure 2).

Where bodies 1 are made of fire-proof compound based on oriented graphite, the latter is normally oriented perpendicularly to the hexagonal surfaces of bodies 1.

As a variant for the hexagonal form, any other shape may be given to bodies 1, for instance, circular, square, triangular. However, it seems that the hexagonal shape should be preferred for the reason explained hereafter.

Bodies 1 are used in the following manner. Assuming that it is question of protecting the surface of the metal bath contained in furnace 2 (see Figure 3) heated by burner 3, a quantity of fire-proof bodies 1 are placed over the fragments of solid metal 4 introduced into furnace 2.

As soon as metal parts 4 nearest to said flame 5 melt, under the action of the heat generated by said flame 5, bodies 1 will float on the liquid thus formed. Figure 4 shows how bodies I lay themselves out over the surface of furnace bath 2, insulating the flame from almost the whole of said surface. It will be seen from Fig. 4 that the hexagonal shape given to bodies 1 is particularly advantageous for covering the bath, owing to the ability of such bodies to intermesh closely and to form an unbroken surface.

If it is desired to obtain a more complete protection of the bath surface, a small amount of flux may be used which will fill up the interstitial empty spaces, such as 6, which may exist primarily between bodies 1 and furnace wall 2 limiting the bath surface.

When such an interstitial flux is used, one may with advantage give the vertical section of the fire-proof floating bodies a slightly sloping form as indicated at 7 (see Figure 5), so that the flux cannot remain on the floating bodies but will flow to the empty spaces between the latter.

It results from the foregoing that by applying the processes as described, one can obtain an insulation of the furnace bath surfaces offering numerous advantages as compared with former processes, namely a saving in the fuel for heating the furnaces, an efficient protection of the baths thanks to which oxidation is reduced, and the maintenance of the molten metal and alloy content, thus resulting in a saving in smelting fluxes.

My invention is, of course, susceptible of various adaptations and not restricted to the specific mode of application and processes set forth.

What I claim is:

1. An element adapted to form part of a protective layer floating on the surface of a furnace melt, comprising a disk-shaped body of refractory material of good thermal conductivity, said body having a sloping upper surface.

2. An element adapted to form part of a protective layer floating on the surface of a furnace melt, comprising a disk-shaped body of refractory material of good thermal conductivity, said body having a sloping upper surface and being of hexagonal configuration.

3. An element adapted to form part of a protective layer floating on the surface of a furnace melt, comprising a disk-shaped body with a sloping upper surface and of refractory material of good thermal conductivity, said material consisting fundamentally of graphite oriented substantially perpendicularly to the major disk faces of said body.

4. An element adapted to form part of a protective layer floating on the surface of a furnace melt, comprising a disk-shaped body of hexagonal configuration and of refractory material of good thermal conductivity, said body having a sloping upper surface, said material consisting fundamentally of graphite oriented substantially perpendicularly to the major disk faces of said body.

5. A protective covering for the surface of a furnace melt, comprising in combination a plurality of diskshaped bodies adapted to form a floating mat on said surface, each of said bodies having a sloping upper face and being of refractory material of good thermal conductivity, and liquid flux interposed between said bodies.

6. A protective-covering for the surface of a furnace melt, comprising in combination a plurality of diskshaped bodies of hexagonal configuration adapted to form v 3 a floating mat on said surface, each of said bodies having a sloping upper face and being of refractory material of good thermal conductivity, and liquid flux interposed between said bodies.

I 1,567,219. Williams Dec. 2-9, 1925 4 Scarbrough Jan. 28, 1930 Bowser June 11, 1940 Tharaldsen Sept. 2, 1941 Clapp et a1 Sept. 25, 1945 

1. AN ELEMENT ADAPTED TO FORM PART OF A PROTECTIVE LAYER FLOATING ON THE SURFACE OF A FURNACE MELT, COMPRISING A DISK-SHAPED BODY OF REFRACTORY MATERIAL OF GOOD THERMAL CONDUCTIVITY, SAID BODY HAVING A SLOPING UPPER SURFACE. 